Thermally expandable resin composition

ABSTRACT

A thermally expandable resin composition containing an epoxy resin, a thermally expandable graphite, and an inorganic filler excluding graphite. The epoxy compound contained in said epoxy resin contains a brominated epoxy compound, and contains, in addition to the brominated epoxy compound, a bisphenol-type epoxy compound and/or an aliphatic epoxy compound, wherein the weight ratio of the brominated epoxy compound to the bisphenol-type epoxy compound and/or aliphatic epoxy compound is in the range 99:1-1:99.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No.PCT/JP2013/006066 filed Oct. 10, 2013, claiming priority based onJapanese Patent Application No. 2012-226460 filed Oct. 11, 2012, thecontents of all of which are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

The present invention relates to an thermally expandable resincomposition, more specifically, to an thermally expandable resincomposition for the use of refractory coating materials for pillars,beams and walls, etc., the use of fireproof sashes, the use of fireproofcompartment passage structures and the use of fireproof doors, etc.

BACKGROUND ART

Materials for a structure such as a building and a ship, etc. arerequired to have fire resistance which doesn't easily catch fire, etc.As an thermally expandable resin composition to be used for the usewhich is required to have fire resistance, it has been proposed anthermally expandable resin composition which forms an expansion residueand prevents spread of a flame, smoke, etc., of a fire, etc., when it isexposed to heat of a fire, etc.

More specifically, as the first thermally expandable resin composition,it has been proposed a thermally expandable resin composition, whichdoes not contain a halogenated compound and has adhesive properties andcontain:

(a) an epoxy functional monomer, an oligomer or an polymer

(b) a particulate phosphorus-containing compound

(c) a thermally expandable graphite

(Patent Document 1, claim 1 to claim 6).

By using this first thermally expandable resin composition, when it israpidly exposed to flame, it is possible to keep a function as anadhesive agent.

Also, as the second thermally expandable resin composition, it has beenproposed a thermally expandable flame resistant resin composition, whichconsists of 100 parts by weight of an epoxy resin, 10 to 300 parts byweight of a thermally expandable graphite subjected to neutralizationtreatment and 50 to 500 parts by weight of an inorganic filler (PatentDocument 2).

By using this second thermally expandable resin composition, it isexcellent in fire resistance because at the time of heating, anexpansion residue is formed, it is possible to retain the shape of saidexpansion residue.

However, molded bodies obtained from these epoxy resin-containingthermally expandable resin composition become hard and fragile.

Therefore, if impact is provided, molded bodies of these epoxyresin-containing thermally expandable are relatively easily broken orcracked in some cases.

The problem that molded bodies of these epoxy resin-containing thermallyexpandable are relatively easily broken or cracked in some casesincreases when used in the environment of low temperature such as a colddistrict, etc.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: JP 2008-506803A-   Patent Document 2: JP 2000-143941A

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

Also, when the present inventors have studied, they have found thatbecause molded bodies of epoxy resin-containing thermally expandableresin composition explained above are relatively high in elastic modulusthe degree of deterioration of a metal blade used when cutting saidmolded bodies is increased.

An object of the present invention is to provide a thermally expandableresin composition which is excellent in fire resistance and stress atbreak and provides molded bodies having relatively low elastic modulus.

Means for Solving Problem

The present inventors have earnestly investigated, and as a result, theyhave found out that a thermally expandable resin composition whichcontains an epoxy resin wherein an epoxy compound contains at least oneof a bisphenol-type epoxy compound, an aliphatic epoxy compound inaddition to a brominated epoxy compound, a thermally expandable graphiteand an inorganic filler, meets the objective of the present invention,and the present inventors accomplished the present invention.

That is, the present invention is to provide

[1] a thermally expandable resin composition which contains an epoxyresin, a thermally expandable graphite and an inorganic filler. An epoxycompound contained in said epoxy resin contains a brominated epoxycompound represented by

in addition to said Formula (21), at least one of a bisphenol-type epoxycompound represented by

Formula (1)

(R₁ and R₂ are each independently a hydrogen atom or a methyl group,R₃-R₆ are each independently any one of a hydrogen atom or a methylgroup. Z is a repeating unit ranging from 1 to 100.) and an aliphaticepoxy compound represented by

Formula (2)

(R is an alkylene group having 1 to 500 carbon atoms, and can contain anoxygen atom. n is a repeating unit ranging from 2 to 4, m is a repeatingunit ranging from 0 to 1 and n+m is the range of 2-4.),

and the ratio of a brominated epoxy compound to at least one of abisphenol-type epoxy compound and an aliphatic epoxy compound rangesfrom 99:1 to 1:99 in weight.

Also, one of the present inventions is to provide

[2] the thermally expandable resin composition described in the [1], inwhich said aliphatic epoxy compound is a bifunctional aliphatic epoxycompound represented by

Formula (3)

(R_(a) is a hydrocarbon radical having 1 to 500 carbon atoms, and cancontain an oxygen atom).

[3] the thermally expandable resin composition described in the [2], inwhich said aliphatic epoxy compound is at least one selected from thegroup consisting of

Formula (3-1)

(R_(b) is an alkylene group having 2 to 4 carbon atoms. r is a repeatingunit ranging from 1 to 500.) and

Formula (3-2)

(R_(c) is an alkylene group having 2 to 10 carbon atoms).

Also, one of the present inventions is to provide

[4] the thermally expandable resin composition described in the [3], inwhich said aliphatic epoxy compound is at least one selected from thegroup consisting of the Formula (4)-Formula (9).

(R₇ is any one of an alkylene group having 1 to 20 carbon atoms,alkenylene group having 1 to 20 carbon atoms or arylene group having 1to 20 carbon atoms.)

(s is a repeating unit ranging from 1 to 500.)

(t is a repeating unit ranging from 1 to 500.)

(u is a repeating unit ranging from 1 to 500.)

Also, one of the present inventions is to provide

[5] the thermally expandable resin composition described in the [1], inwhich said aliphatic epoxy compound contains Formula (2a)

(R is an alkylene group having 1 to 500 carbon atoms, and can contain anoxygen atom. q is a repeating unit ranging from 3 to 4, p is a repeatingunit ranging from 0 to 1 and p+q is the range of 3-4).

Also, one of the present inventions is to provide

[6] the thermally expandable resin composition described in the [5], inwhich said aliphatic epoxy compound is at least one selected from thegroup consisting of the Formula (10)-Formula (12).

Also, one of the present inventions is to provide

[7] the thermally expandable resin composition described in any one ofthe [1] to [6], in which said epoxy resin contains an aminocompound-containing epoxy curing agent, and said aminocompound-containing epoxy curing agent contains at least one selectedfrom the group consisting of Formula (13)-Formula (16).R₈—O—R₉—NH₂  Formula (13)

(R₈ is an alkylene group having 1 to 20 carbon atoms, alkenyl grouphaving 1 to 20 carbon atoms or aryl group having 1 to 20 carbon atoms,may contain an oxygen atom. Also, R₉ is an alkylene group having 1 to 20carbon atoms, alkenylene group having 1 to 20 carbon atoms or arylenegroup having 1 to 20 carbon atoms, may contain an oxygen atom.)

(R₁₀ and R₁₁ are each independently a hydrogen atom, an alkyl grouphaving 1 to 20 carbon atoms, alkenyl group having 1 to 20 carbon atomsor aryl group having 1 to 20 carbon atoms.)

(R₁₂, R₁₃ and R₁₄ are each independently a hydrogen atom, an alkyl grouphaving 1 to 20 carbon atoms, alkenyl group having 1 to 20 carbon atomsor aryl group having 1 to 20 carbon atoms, may contain an oxygen atom.)R₁₅—NH₂  Formula (16)

(R₁₅ is each independently an alkyl group having 1 to 20 carbon atoms,alkenyl group having 1 to 20 carbon atoms or aryl group having 1 to 20carbon atoms, may contain an oxygen atom.)

Also, one of the present inventions is to provide

[8] the thermally expandable resin composition described in any one ofthe [1] to [7], in which said inorganic filler contains a phosphoruscompound and a metal compound.

Also, one of the present inventions is to provide

[9] the thermally expandable resin composition described in any one ofthe [1] to [8], in which said inorganic filler is at least one selectedfrom the group consisting of ammonium polyphosphate, calcium carbonate,melamine polyphosphate and titanium oxide.

Also, one of the present inventions is to provide

[10] the thermally expandable resin composition described in any one ofthe [1] to [9], which is used in refractory coating materials forpillars, beams and walls, in fireproof sashes, in fireproof compartmentpassage structures, in fireproof doors.

Effects of the Invention

A thermally expandable resin composition of the present invention cangive molded bodies having excellent fire resistance, stress at breakafter thermal expansion and relatively low elastic modulus.

EMBODIMENTS TO CARRY OUT THE INVENTION

A brominated epoxy compound to be used in an epoxy resin to be used inthe present invention is firstly explained.

Said brominated epoxy compound is represented by the Formula (21).

Said brominated epoxy compound can be obtained by the method in which abrominated bisphenol compound represented by the Formula (22) is reactedwith an epichlorohydrin.

Incidentally, when a brominated bisphenol compound represented by saidFormula (22) is glycidyl-etherified, it contains components produced bythe reaction in the manufacturing process such as self-condensate by thereaction of a hydroxyl group contained in said brominated bisphenolcompound with a glycidyl group and a reactant adding water to a glycidylgroup, etc., in some cases. The case of a compound which contains thefollowing glycidyl ether group is the same as above.

Next, said bisphenol-type epoxy compound to be used in the presentinvention is explained.

Said bisphenol-type epoxy compound is represented by the Formula (1).

Here, R₁ and R₂ each independently a hydrogen atom or a methyl group,R₃-R₆ are each independently any one of a hydrogen atom or a methylgroup. Z is a repeating unit ranging from 1 to 100.

A bisphenol-type epoxy compound to be used in the present invention maybe specifically mentioned, for example, a material represented by theFormula (17)-Formula (18), etc.

Here, X is a repeating unit ranging from 1 to 100.

Said Formula (17) is corresponding to the case that R₁-R₆ of saidFormula (1) are hydrogen atoms.

Y is a repeating unit ranging from 1 to 100.

Said Formula (18) is corresponding to the case that R₁ and R₂ of saidFormula (1) are methyl groups, R₃-R₆ are hydrogen atoms.

A kind or two or more kinds of said bisphenol-type epoxy compound may beused.

Also, an aliphatic epoxy compound to be used in the present invention isrepresented by the Formula (2).

Here, R is an alkylene group having 1 to 500 carbon atoms, and cancontain an oxygen atom. Also, n is a repeating unit ranging from 2 to 4,m is a repeating unit ranging from 0 to 1 and n+m is the range of 2-4.

An aliphatic epoxy compound to be used in the present invention may bementioned, for example, a bifunctional aliphatic epoxy compound and apolyfunctional aliphatic epoxy compound having three or more functionalgroups, etc.

A kind or two or more kinds of said aliphatic epoxy compound may beused.

An aliphatic epoxy compound to be used in the present invention may bespecifically mentioned, for example, a bifunctional aliphatic epoxycompound represented by the Formula (3).

Here, R_(a) is a hydrocarbon radical having 1 to 500 carbon atoms, andcan contain an oxygen atom.

Said Formula (3) may be specifically mentioned, for example, the Formula(3-1), (3-2), etc.

Here, Rb is an alkylene group having 2 to 4 carbon atoms. Said alkylenegroup may be mentioned, for example, an ethylene group, a propylenegroup, a butylene group and isomers of these. Also, r is a repeatingunit ranging from 1 to 500, preferably a repeating unit ranging from 2to 500.

R_(c) is an alkylene group having 2 to 10 carbon atoms. Said alkylenegroup may be mentioned, for example, an ethylene group, a propylenegroup, a butylene group, a pentylene group, a hexylene group, aheptylene group, an octylene group, a nonylene group, a decanylene groupand isomers of these.

R_(c) is preferably an alkylene group having 2 to 6 carbon atoms.

A bifunctional aliphatic epoxy compound to be used in the presentinvention may be mentioned, for example, a material represented by theFormula (4)-Formula (9), etc.

Here, R₇ is an alkylene group having 1 to 20 carbon atoms, alkenylenegroup having 1 to 20 carbon atoms or arylene group having 1 to 20 carbonatoms

s is a repeating unit ranging from 1 to 500.

t is a repeating unit ranging from 1 to 500.

u is a repeating unit ranging from 1 to 500.

An aliphatic epoxy compound to be used in the present invention may bespecifically mentioned, for example, a polyfunctional aliphatic epoxycompound having three or more functional groups represented by theFormula (2a).

R is an alkylene group having 1 to 500 carbon atoms, and can contain anoxygen atom. q is a repeating unit ranging from 3 to 4. p is a repeatingunit ranging from 0 to 1 and p+q is the range of 3-4.

A polyfunctional aliphatic epoxy compound having three or morefunctional groups may be specifically mentioned, for example, theFormula (10)-Formula (12), etc.

Next, a combination of said brominated epoxy epoxy compound and at leastone of a bisphenol-type epoxy compound and an aliphatic epoxy compoundis explained.

[(Z) a Combination of Said Brominated Epoxy Epoxy Compound and at LeastOne of a Bisphenol-Type Epoxy Compound and an Aliphatic Epoxy Compound]

(X is a repeating unit ranging from 1 to 500.)

(Y is a repeating unit ranging from 1 to 500.)

(R₇ is an alkylene group having 1 to 20 carbon atoms, alkenylene grouphaving 1 to 20 carbon atoms or arylene group having 1 to 20 carbonatoms.)

(s is a repeating unit ranging from 1 to 500.)

(t is a repeating unit ranging from 1 to 500.)

(u is a repeating unit ranging from 1 to 500.)

For example, a combination of at least one of said (Z-1) and (Z-2) as anessential component and at least one selected from the group consistingof said (Z-3)-(Z-13) may be mentioned.

Molded bodies obtained by molding a thermally expandable resincomposition using a combination of the a brominated epoxy epoxy compoundand at least one of a bisphenol-type epoxy compound and an aliphaticepoxy compound have low elastic modulus, excellent fire resistance andstress at break after thermal expansion.

A bisphenol-type epoxy compound and an aliphatic epoxy compound to beused in the present invention are preferably at least one selected fromthe group consisting of said Formula (4)-Formula (12), are morepreferably at least one selected from the group consisting of Formula(8), Formula (10) and Formula (11).

Next, a mixing ratio of said brominated epoxy epoxy compound to at leastone of said bisphenol-type epoxy compound and aliphatic epoxy compoundis explained.

A mixing ratio of said brominated epoxy epoxy compound to at least oneof said bisphenol-type epoxy compound and aliphatic epoxy compoundranges from 99:1 to 1:99 in weight.

When said brominated epoxy epoxy compound and said bisphenol-type epoxycompound are used in combination, an expansion residue obtained afterthermal expansion is expected to have good hardness. Therefore, a mixingratio of said brominated epoxy epoxy compound to said bisphenol-typeepoxy compound preferably ranges from 95:5 to 5:95 in weight.

Also, a mixing ratio of said brominated epoxy epoxy compound to saidbisphenol-type epoxy compound more preferably ranges from 50:50 to 5:95,further preferably ranges from 30:70 to 10:90, most preferably rangesfrom 25:75 to 15:85 in weight because compatibility between saidbrominated epoxy epoxy compound and said bisphenol-type epoxy compoundis improved, and a thermally expandable resin composition according tothe present invention is easily handled.

Also, when said brominated epoxy epoxy compound and said aliphatic epoxycompound are used in combination, a thermally expandable resincomposition according to the present invention is easily handled, andfire resistance does not reduce much. Therefore, a mixing ratio of saidbrominated epoxy epoxy compound to said aliphatic epoxy compoundpreferably ranges from 95:5 to 5:95, more preferably ranges from 95:5 to10:90, further preferably ranges from 95:5 to 50:50, most preferablyranges from 95:5 to 80:20 in weight.

Next, an epoxy curing agent contained in an epoxy resin to be used inthe present invention is explained.

An epoxy curing agent to be used in the present invention contains anamino compound.

For example, an amino compound-containing epoxy curing agent whichcontains the Formula (13)-Formula (16), etc. may be specificallymentioned.R₈—O—R₉—NH₂  Formula (13)

(R₈ is an alkyl group having 1 to 20 carbon atoms, alkenyl group having1 to 20 carbon atoms or aryl group having 1 to 20 carbon atoms. Also, R₉is an alkylene group having 1 to 20 carbon atoms, alkenylene grouphaving 1 to 20 carbon atoms or arylene group having 1 to 20 carbonatoms.)

(R₁₀ and R₁₁ are each independently a hydrogen atom, an alkyl grouphaving 1 to 20 carbon atoms, alkenyl group having 1 to 20 carbon atomsor aryl group having 1 to 20 carbon atoms.)

(R₁₂, R₁₃ and R₁₄ are each independently a hydrogen atom, an alkyl grouphaving 1 to 20 carbon atoms, alkenyl group having 1 to 20 carbon atomsor aryl group having 1 to 20 carbon atoms.)R₁₅—NH₂  Formula (16)

(R₁₅ is each independently an alkyl group having 1 to 20 carbon atoms,alkenyl group having 1 to 20 carbon atoms or aryl group having 1 to 20carbon atoms.)

For an amino compound-containing epoxy curing agent to be used in thepresent invention, a kind or two or more kinds of the Formula(13)-Formula (16) may be preferably used.

For an amino compound-containing epoxy curing agent,3-lauryloxypropylamine, hexamethylenediamine, oleylamine, xylenediamineand derivatives of these, etc. may be more preferably used.

Next, an inorganic filler is explained.

Said inorganic filler is not particularly limited, and may bespecifically mentioned, for example, zinc borate, boric acid, boricoxide, silica, diatomaceous earth, alumina, zinc oxide, titanium oxide,calcium oxide, magnesium oxide, ferric oxide, tin oxide, antimony oxide,ferrite, calcium hydroxide, magnesium hydroxide, aluminum hydroxide,basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinccarbonate, barium carbonate, dawsonite, potassium salt such ashydrotalcite, calcium sulfate, barium sulfate, gypsum fibers, calciumsilicate, talc, clay, mica, montmorillonite, bentonite, activated clay,sepiolite, imogolite, sericite, glass fibers, glass beads, silica seriesballoons, aluminum nitride, boron nitride, silicon nitride, carbonblack, graphite, carbon fibers, carbon balloons, charcoal powder,various metal powders, potassium titanate, magnesium sulfate, leadzirconia titanate, aluminum borate, molybdenum sulfide, silicon carbide,stainless fibers, zinc borate, various magnetic powders, slag fibers,fly ash, inorganic series phosphorus compound, silica-alumina fiber,alumina fiber, silica fiber, zirconia fiber, etc.

A kind or two or more kinds of these may be used.

Also, a phosphorus compound and a thermally expandable component, etc.may be added to a thermally expandable resin composition to be used inthe present invention

The phosphorus compound is not particularly limited, and may bementioned, for example,

red phosphorus,

various kinds of phosphoric acid ester such as triphenyl phosphate,tricresyl phosphate, trixylenyl phosphate, cresyldiphenyl phosphate,xylenyldiphenyl phosphate, etc.,

bisphenol A-derived condensed phosphoric ester such as PX-200 (availablefrom Daihachi Chemical Industry Co., Ltd.), CR-733S (available fromDaihachi Chemical Industry Co., Ltd.), etc.,

condensed type phosphoric ester such as xylenol-derived condensedphosphoric ester such as CR-741S (available from Daihachi ChemicalIndustry Co., Ltd.), etc.,

Halogen-containing phosphoric ester which contains halogen such aschlorine, etc. in the structure of the phosphoric ester and condensedtype phosphoric ester, and Halogen-containing condensed type phosphoricester,

a phosphate metallic salt such as sodium phosphate, potassium phosphate,magnesium phosphate, etc.,

ammonium polyphosphates,

compounds represented by the Formula (19), etc.

A kind or two or more kinds of these phosphorus compound may be used.

Among these, in the viewpoint of fireproof properties, red phosphorus,the compound represented by the chemical formula, and ammoniumpolyphosphates are preferred, and ammonium polyphosphates are morepreferred in the points of properties, safety, cost, etc.

In the Formula (19), R¹⁶ and R¹⁸ represent hydrogen, a linear orbranched alkyl group having 1 to 16 carbon atoms or an aryl group having6 to 16 carbon atoms.

R¹⁷ represents a hydroxyl group, a linear or branched alkyl group having1 to 16 carbon atoms, a linear or branched alkoxyl group having 1 to 16carbon atoms, an aryl group having 6 to 16 carbon atoms, or an aryloxygroup having 6 to 16 carbon atoms.

The compound represented by the chemical formula may be mentioned, forexample, methylphosphonic acid, methylphosphonic acid dimethyl,methylphosphonic acid diethyl, ethylphosphonic acid, propylphosphonicacid, buthylphosphonic acid, 2-methylpropylphosphonic acid,t-buthylphosphonic acid, 2,3-dimethyl-buthylphosphonic acid,octylphosphonic acid, phenylphosphonic acid, dioctylphenyl phosphonate,dimethyl phosphinic acid, methylethyl phosphinic acid, methylpropylphosphinic acid, diethyl phosphinic acid, dioctyl phosphinic acid,phenyl phosphinic acid, diethylphenyl phosphinic acid, diphenylphosphinic acid and bis(4-methoxyphenyl)phosphinic acid, etc.

Above all, whereas t-butylphosphonic acid is expensive, it is preferredin the point of high fire retardant properties.

Whereas ammonium polyphosphates are not particularly limited, and may bementioned, for example, ammonium polyphosphate, melamine-modifiedammonium polyphosphate, ammonium polyphosphate, piperazinepolyphosphate, ammonium polyphosphate amide, and said ammoniumpolyphosphates to which melamine and/or pentaerythritol, etc. are addedas a foaming agent, in the points of fire retardant properties, safety,a cost, handling properties, etc., ammonium polyphosphate is preferred.

Commercially available products may be mentioned, for example, “tradename: EXOLIT AP422” and “trade name: EXOLIT AP462” available fromClariant K.K., etc.

The phosphorus compound is considered to promote expansion of the metalcarbonate by reacting with a metal carbonate such as calcium carbonate,zinc carbonate, etc., and in particular, when ammonium polyphosphate isused as the phosphorus compound, high expansion effect can be obtained.Also, it acts as an effective aggregate, and forms a residue having highshape retaining properties after burning.

Next, said thermally expandable graphite is explained.

Said thermally expandable graphite is a material which expands at thetime of heating, and it is possible to obtain a material having adifferent thermal expansion initiation temperature as commerciallyavailable products.

Said thermally expandable graphite is a conventionally known material,which is a graphite intercalation compound formed by treating powdersuch as natural scaly graphite, pyrolytic graphite, kish graphite, etc.,with an inorganic acid such as conc. sulfuric acid, nitric acid, selenicacid, etc., and a strong oxidizing agent such as conc. nitric acid,perchloric acid, a perchlorate, a permanganate, a dichromate, hydrogenperoxide, etc., and is a kind of a crystalline compound which retains alayered structure of the carbon.

The thermally expandable graphite obtained by subjecting to an acidtreatment as mentioned above is preferably used by further neutralizingwith ammonia, an aliphatic lower amine, an alkali metal compound, analkaline earth metal compound, etc.

Said aliphatic lower amine may be mentioned, for example,monomethylamine, dimethylamine, trimethylamine, ethylamine, propylamine,butylamine, etc.

Said alkali metal compound and said alkaline earth metal compound may bementioned, for example, a hydroxide, an oxide, a carbonate, a sulfate,an organic acid salt, etc., such as potassium, sodium, calcium, barium,magnesium, etc.

A grain size of the thermally expandable graphite is preferably amaterial in the range of 20-200 mesh.

If the grain size is less than 20 mesh, a degree of expansion of thegraphite is small, and a sufficient expansion residue can be difficultlyobtained, while if the grain size becomes large exceeding 200 mesh,there is a merit that a degree of expansion of the graphite is large,but dispersibility becomes poor when it is mixed and kneaded with saidthe epoxy resin, and physical properties are likely lowered.

Commercially available products of the thermally expandable graphitesubjected to neutralization treatment may be mentioned, for example,“GRAFGUARD#160” and “GRAFGUARD#220” available from UCAR CARBON Co.,Inc., and “GREP-EG” available from Tosoh Corporation, etc.

Also, said inorganic filler that is used in a thermally expandable resincomposition layer which acts as a role of an aggregate, and contributesto improve strength of the expansion residue formed after heating or toincrease heat capacity of the same is preferred.

More specifically, a metal carbonate represented by calcium carbonateand zinc carbonate, and a hydrated inorganic product represented byaluminum hydroxide and magnesium hydroxide which act as a role like anaggregate as well as provide a heat absorption effect at the time ofheating are preferred, and an alkali metal, an alkaline earth metal, anda metal carbonate of Group IIb of the Periodic Table or a mixture ofthese compounds and the hydrated inorganic product are preferred.

When an inorganic filler to be used in the present invention is aparticulate, the particle size is preferably within the range of 0.5-200μm, more preferably within the range of 1-50 μm.

When the amount of the inorganic filler to be added is a little, thedispersibility markedly affects the properties so that a material havinga small particle size is preferred, and when the particle size is 0.5 μmor more, secondary aggregation can be prevented and deterioration ofdispersibility can be prevented.

Also, when an amount of the inorganic filler to be added is much, aviscosity of the resin composition becomes high with the progress ofhighly filling, and moldability is lowered, but in the point that theviscosity of the resin composition can be lowered by making the particlesize large, that a material having a large particle size is preferredamong the range.

Incidentally, if the particle size is 200 μm or less, lowering insurface properties of the molded product and the mechanical propertiesof the resin composition can be prevented.

A metal carbonate, a metal oxide such as titanium oxide, zinc oxide,etc. which acts as a role like an aggregate in the same way, a hydratedinorganic product such as aluminum hydroxide and magnesium hydroxide,etc. which act as a role like an aggregate as well as provide a heatabsorption effect at the time of heating are preferably used; amongthese, a metal carbonate or a metal oxide is more preferably usedbecause their effect of an aggregate is high; calcium carbonate,titanium oxide, zinc oxide, silicon oxide are further preferably used;and calcium carbonate is most preferably used.

When a particle size of the hydrated inorganic product is small, thebulk becomes large and highly filling becomes difficult so that amaterial having a large particle size is preferred to accomplish higherfilling for heightening the dehydration effect. More specifically, whenthe particle size is 18 μm, it has been known that a filling limitamount increases about 1.5-fold as compared with that of the particlesize of 1.5 μm. Further, higher filling is possible by using a materialhaving large particle size and a material having small particle size incombination.

Commercially available products of said hydrated inorganic product maybe mentioned, for example, as aluminum hydroxide, “trade name: HIGILITEH-42M” (available from SHOWA DENKO K.K.) having a particle size of 1 μm,“trade name: HIGILITE H-31” (available from SHOWA DENKO K.K.) having aparticle size of 18 μm, etc.

Commercially available products of said calcium carbonate may bementioned, for example, “trade name: Whiton SB Red” (available fromSHIRAISHI CALCIUM KAISHA, Ltd.) having a particle size of 1.8 μm, “tradename: BF300” (available from BIHOKU FUNKA KOGYO CO., LTD.) having aparticle size of 8 μm, etc.

Next, the formulation of an epoxy resin, a phosphorus compound as aninorganic filler, and a thermally expandable resin composition, etc.which contain a thermally expandable graphite, etc. is explained.

Said thermally expandable resin composition preferably contains saidthermally expandable graphite in the range of 20 to 350 parts by weightand said inorganic filler in the range of 50 to 400 parts by weightbased on 100 parts by weight of said epoxy resin. Also, the sum of saidthermally expandable graphite and said inorganic filler is preferably inthe range of 200 to 600 parts by weight.

Such a thermally expandable resin composition expands by heat to form anexpansion residue. According to this formulation, said thermallyexpandable resin composition expands by heat such as a fire, etc., and anecessary volume expansion rate can be obtained. After the expansion, aresidue having a predetermined heat insulating properties as well as apredetermined strength can be formed, and a stable fireproof performancecan be accomplished.

If the amount of said thermally expandable graphite is 20 or more partsby weight, an expansion ratio is improved, and sufficient fireresistance and fireproof performance can be obtained.

On the other hand, if the amount of a thermally expandable graphite is350 or less parts by weight, a cohesive force is improved, and astrength of a molded product increased.

Also, if the amount of said inorganic filler is 50 or more parts byweight, the amount of a residual volume after burning can be kept, sothat a sufficient expansion residue can be obtained. Further, a ratio ofthe combustible material is decreased, so that fire retardant propertiesare improved.

On the other hand, if the amount of an inorganic filler is 400 or lessparts by weight, a formulation ratio of an epoxy resin is increased, sothat a sufficient cohesive force can be obtained, and strength as amolded product can be kept.

If the total amount of a thermally expandable graphite and an inorganicfiller in said thermally expandable resin composition is 200 or moreparts by weight, the amount of a thermal expansion residue after burningcan be kept, and sufficient fireproof performance can be obtained, whileif it is 600 or less parts by weight, lowering in mechanical propertiescan be prevented and it can be endured for a long time.

Further, said resin composition and thermally expandable resincomposition to be used in the present invention may contain, in additionto an antioxidant such as a phenol series, an amine series, a sulfurseries, etc., an additive such as a metal damage preventing agent, anantistatic agent, a stabilizer, a cross-linking agent, a lubricant, asoftening agent, a pigment, etc., and a tackifier such as a polybutene,a petroleum resin, etc., if necessary, within the range which does notimpair the objects of the present invention.

Next, a manufacturing method of said thermally expandable resincomposition is explained.

The manufacturing method of said thermally expandable resin compositionis not particularly limited, and said thermally expandable resincomposition can be obtained, for example, by the method in which saidthermally expandable resin composition is suspended in an organicsolvent or melted by heating to prepare a paint state respectively,

the method in which it is dispersed in an organic solvent to prepare aslurry, etc. or the method in which said thermally expandable resincomposition is melted under heating, etc.

Above all, a step to remove an organic solvent is not necessary, so thatnot to use an organic solvent is preferred.

Said thermally expandable resin composition can be obtained by mixingand kneading the respective components by using a conventionally knowndevice such as a single screw extruder, a twin screw extruder, a Bunbarymixer, a mixing and kneading roller, a Raikai mixer, a planetarystirring machine, etc.

Also, when said thermally expandable resin composition is manufactured,unreacted components of an epoxy resin and an epoxy curing agent areseparately mixed and kneaded with a filler, and the material can beobtained by mixing and kneading these immediately before the molding byusing a static mixer, a dynamic mixer, etc.

The present invention is explained in more detail on the basis ofExamples below, but the present invention is not limited by thefollowing Examples.

Example 1

[(Z) A Combination of Said Brominated Epoxy Epoxy Compound and at LeastOne of a Bisphenol-Type Epoxy Compound and an Aliphatic Epoxy Compound]

(X is a repeating unit ranging from 1 to 100.)

10.9 parts by weight of tetrabromobisphenol-A-diglycidyl-ether(available from Nippon Steel Chemical Co., Ltd., trade name: YDB-400, anepoxy equivalent: 403.1 g/eq. Hereinafter referred to as “A-10”.) as the(Z-1),

45.4 parts by weight of bisphenol-F-diglycidyl-ether (available fromMitsubishi Chemical Corporation, trade name: E807, an epoxy equivalent:168 g/eq. Hereinafter referred to as “A-1”.) as the (Z-3),

43.7 parts by weight of an amino compound which is prepared by mixing3-lauryloxypropyl-1-amine with hexamethylenediamine derivative(available from Mitsubishi Chemical Corporation, trade name: FL052) at aweight ratio of 6:4 (an amine equivalent: 167.3 g/eq., on the basis ofthe active hydrogen. Hereinafter referred to as “B-1”.), as an epoxycuring agent,

90 parts by weight of ammonium polyphosphates (available from ClariantK.K. trade name: AP-422. Hereinafter referred to as “C-1”.), as a kindof an inorganic filler,

90 parts by weight of a thermally expandable graphite (available fromTosoh Corporation, trade name: GREP-EG. Hereinafter referred to as“C-2”.), as a kind of an inorganic filler,

90 parts by weight of calcium carbonate (available from BIHOKU FUNKAKOGYO CO., LTD., trade name: Whiton BF-300. Hereinafter referred to as“C-3”.), as a kind of an inorganic filler,

are weighed to 370 g in total by a three neck flask of 1000 mL, and athermally expandable resin composition is made by stirring for 10minutes at a temperature of 25° C. using a mechanical stirrer.

The obtained thermally expandable resin composition 170 g is puttedbetween polyethylene terephthalate sheets subjected to releasingtreatment to be 25 cm×25 cm×2 mm, and a thermally expandable resincomposition sheet is made by pressing for 30 seconds at a temperature of40° C. using a heating electric press.

An epoxy resin sheet is made by heating said thermally expandable resincomposition sheet to be cured for 24 hours at a temperature of 90° C.using an oven.

Also, the obtained thermally expandable resin composition 135 g isputted between polyethylene terephthalate sheets subjected to releasingtreatment to be 25 cm×25 cm×1.5 mm, and a thermally expandable resincomposition sheet is made by pressing for 30 seconds at a temperature of40° C. using a heating electric press. An epoxy resin sheet is made byheating said thermally expandable resin composition sheet to be curedfor 24 hours at a temperature of 90° C. using an oven.

The test of stress at break is carried out using the obtained 1.5 mmepoxy resin sheet. Also, measurement of elastic modulus is carried outusing the 2 mm epoxy resin sheet.

Incidentally, (A) components (“A-1” and“A-10”) and (B) components(“B-1”) are mixed in accordance with the ratio which makes the ratio ofan epoxy equivalent of an epoxy monomer to an active hydrogen equivalentof a curing agent 105:100-100:105. This relation is the same for thefollowing cases.

The obtained epoxy resin sheet is evaluated on the following criteria.

[Stress at Break]

-   -   A specimen of 98 mm×98 mm×1.5 mm is heated in an electric        furnace for 30 minutes at a temperature of 600° C. using the        present invention product and the comparative invention product        obtained from the manufacturing examples.    -   Measurement of stress at break is an index of shape retaining        properties of a thermally expandable inorganic material of the        present invention product and the comparative invention product        after thermal expansion; stress at break of a sample after        heating is measured using a compression testing machine        (available from Kato tech Co., Ltd. “Finger Feeling Tester”) by        a 0.25 cm² penetrator at 0.1 cm/s in compression speed.

[Bending Elastic Modulus]

Bending elastic modulus of the present invention product and comparativeinvention product is measured under temperature: 0° C., test speed: 5mm/s, specimen: W25 mm×L30 mm×T2 mm, inter-fulcrum distance: 24 mm, onJIS K7171 using Tenshiron available from Orientec Co., Ltd.

In the case of (Z) a combination of said brominated epoxy epoxy compoundand at least one of a bisphenol-type epoxy compound and an aliphaticepoxy compound, said stress at break is preferably 0.6 kgf or more, andelastic modulus is preferably 50 N/mm² or less.

The results are shown in Table 1.

As is evident from Table 1, an epoxy resin sheet obtained by curing athermally expandable resin composition according to Example 1 isrelatively low in elastic modulus, and is excellent in fire resistanceand stress at break.

The formulation used in Example 1 and the results are shown in Table 1.

Example 2

In the case of Example 1, 11.2 parts by weight of “A-10” are used, 39.3parts by weight of “A-1” are used. Also, in addition to “A-10” and“A-1”, the (Z-6) is used.

(R₇ is an alkylene group having 1 to 20 carbon atoms, alkenylene grouphaving 1 to 20 carbon atoms or arylene group having 1 to 20 carbonatoms.)

As the (Z-6), 4.7 parts by weight of dimer-modified epoxy (an epoxyequivalent: 422 g/eq. Hereinafter referred to as “A-3”.) are used.

Also, 43.9 parts by weight of “B-1” are used. The formulation used inExample 2 and the results are shown in Table 1.

Example 3

In the case of Example 1, 31.6 parts by weight of “A-10” are used; the(Z-5) is used instead of “A-1”.

As the (Z-5), 31.5 parts by weight of hexamethylene diglycidyl ether (anepoxy equivalent: 157 g/eq. Hereinafter referred to as “A-2”.)

Also, completely the same experiment as in Example 1 is carried out,except that 36.9 parts by weight of “B-1” are used.

The formulation used in Example 3 and the results are shown in Table 1.

Example 4

Completely the same experiment as in Example 1 is carried out, exceptthat 54.4 parts by weight of “A-10” are used, 13.6 parts by weight of“A-1” are used, and 32.0 parts by weight of “B-1” are used.

The formulation used in Example 4 and the results are shown in Table 1.

Example 5

In the case of Example 1, 54.6 parts by weight of “A-10”, 13.6 parts byweight of “A-1” are used.

Also, completely the same experiment as in Example 1 is carried out,except that 31.8 parts by weight of a mixture of a xylenediaminederivative:oleylamine=6:4 (an active hydrogen equivalent: 165.0 g/eq. Axylenediamine derivative is prepared by reacting 1 mole of butylglycidylether and 1 mole of dodecylglycidyl ether with 1 mole ofmetaxylenediamine. Hereinafter referred to as “B-2”.) are used as anepoxy curing agent instead of “B-1”.

The formulation used in Example 5 and the results are shown in Table 1.

Example 6

In the case of Example 1, completely the same experiment as in Example 1is carried out, except that 62.4 parts by weight of “A-10”, 7.0 parts byweight of “A-1”, 30.6 parts by weight of “B-1” are used.

The formulation used in Example 6 and the results are shown in Table 1.

Example 7

In the case of Example 1, 55.4 parts by weight of “A-10” are used.

Also, the (Z-9) is used instead of “A-1”.

(u is a repeating unit ranging from 1 to 500.)

As the (Z-9), 13.8 parts by weight of polyethylene glycol glycidyl ether(available from Nagase ChemteX Corporation, a polymerization degreeaverage 9, EX-830, an epoxy equivalent: 268 g/eq. Hereinafter referredto as “A-6”.)

Also, completely the same experiment as in Example 1 is carried out,except that 30.8 parts by weight of “B-1” are used.

The formulation used in Example 7 and the results are shown in Table 1.

Example 8

In the case of Example 1, 55.4 parts by weight of “A-10” are used, 13.8parts by weight of “A-6” instead of “A-1”.

Also, completely the same experiment as in Example 1 is carried out,except that 30.8 parts by weight of “B-2” instead of “B-1”.

The formulation used in Example 8 and the results are shown in Table 1.

Example 9

In the case of Example 1, 52.7 parts by weight of “A-10” are used.

Also, the (Z-4) is used instead of “A-1”.

(Y is a repeating unit ranging from 1 to 100.)

As the (Z-4), 15.7 parts by weight of bisphenol-A-type epoxy monomer(available from Mitsubishi Chemical Corporation, trade name: E828, anepoxy equivalent: 179 g/eq. Hereinafter referred to as “A-13”.) areused.

Also, completely the same experiment as in Example 1 is carried out,except that 31.6 parts by weight of “B-2” are used instead of “B-1”.

The formulation used in Example 9 and the results are shown in Table 1.

Example 10

In the case of Example 1, 54.6 parts by weight of “A-10” are used, 13.6parts by weight of “A-1” are used.

Also, 31.8 parts by weight of “B-2” are used instead of “B-1”.

Also, completely the same experiment as in Example 1 is carried out,except that 90 parts by weight of titanium oxide (available from KishidaChemical Co., Ltd., product code: 020-78675. Hereinafter referred to as“C-5”.) are used as a kind of an inorganic filler instead of aninorganic filler “C-3”.

The formulation used in Example 10 and the results are shown in Table 1.

Example 11

In the case of Example 1, 54.6 parts by weight of “A-10” are used, 13.6parts by weight of “A-1” are used.

Also, 31.8 parts by weight of “B-2” are used instead of “B-1”.

Also, completely the same experiment as in Example 1 is carried out,except that 90 parts by weight of melamine polyphosphate (available fromNissan Chemical Industries, Ltd., trade name: PHOSMEL-200. Hereinafterreferred to as “C-4”.) are used as a kind of an inorganic filler insteadof an inorganic filler “C-1”.

The formulation used in Example 11 and the results are shown in Table 1.

Comparative Example 1

In the case of Example 1, 41.3 parts by weight of “A-1” are used, 10.3parts by weight of “A-3” are used instead of “A-10”, and 48.4 parts byweight of “B-1” are used. Also, completely the same experiment as inExample 1 is carried out, except that “A-10” is not used.

The formulation used in Comparative Example 1 and the results are shownin Table 2.

Comparative Example 2

In the case of Example 1, 40.0 parts by weight of “A-1” are used, 10.0parts by weight of “A-2” are used, and 50.0 parts by weight of “B-2” areused instead of “B-1”. Also, completely the same experiment as inExample 1 is carried out, except that “A-10” is not used.

The formulation used in Comparative Example 2 and the results are shownin Table 2.

Comparative Example 3

In the case of Comparative Example 1, 50.0 parts by weights of “A-1” areused, 50.0 parts by weights of “B-1” are used. Also, completely the sameexperiment as in Comparative Example 1 is carried out, except that “A-3”is not used.

The formulation used in Comparative Example 3 and results are shown inTable 2.

Comparative Example 4

In the case of Comparative Example 1, 47.1 parts by weight of “A-1” areused, 47.8 parts by weight of “B-1” are used. Also, completely the sameexperiment as in Comparative Example 1 is carried out, except that 5.1parts by weight of “A-6” are used instead of “A-3”.

The formulation used in Comparative Example 4 and results are shown inTable 2.

Comparative Example 5

In the case of Comparative Example 1, 47.9 parts by weight of “B-1” areused. Also, completely the same experiment as in Comparative Example 1is carried out, except that the 52.1 parts by weight of “A-13” are usedinstead of “A-1” and “A-3”.

The formulation used in Comparative Example 5 and results are shown inTable 2.

TABLE 1 Example 1 2 3 4 5 6 7 8 9 10 11 Epoxy A-10 10.9 11.2 31.6 54.454.6 62.4 55.4 55.4 52.7 54.6 54.6 A-1 45.4 39.3 — 13.6 13.6 7.0 — — —13.6 13.6 A-2 — — 31.5 — — — — — — — — A-3 — 4.7 — — — — — — — — — A-6 —— — — — — 13.8 13.8 — — — A-13 — — — — — — — — 15.7 — — Curing Agent B-143.7 43.9 36.9 32.0 — 30.6 30.8 — — — — B-2 — — — — 31.8 — — 30.8 31.631.8 31.8 Inorganic C-1 90 90 90 90 90 90 90 90 90 90 — Filler C-2 90 9090 90 90 90 90 90 90 90 90 (Including C-3 90 90 90 90 90 90 90 90 90 —90 Graphite) C-4 — — — — — — — — — — 90 C-5 — — — — — — — — — 90 —Results Stress at Break 0.68 0.65 0.69 0.73 0.75 0.77 0.74 0.78 0.710.65 0.63 (kgf/cm²) Bending Elastic 42.8 23.5 8.6 38.6 39.8 35.6 21.516.6 44.1 45.8 47.9 Modulus (N/mm²)

TABLE 2 Comparative Example 1 2 3 4 5 Epoxy A-1 41.3 40.0 50.0 47.1 —A-2 — 10.0 — — — A-3 10.3 — — — — A-6 — — — 5.1 — A-13 — — — — 52.1Curing B-1 48.4 — 50.0 47.8 47.9 Agent B-2 — 50.0 — — — Inorganic C-1 9090 90 90 90 Filler C-2 90 90 90 90 90 (Including C-3 90 90 90 90 90Graphite) Results Stress at Break 0.37 0.40 0.58 0.52 0.59 (kgf/cm²)Bending Elastic 6.28 6.8 46.3 20.6 53.1 Modulus (N/mm²)

UTILIZABLE FIELD IN INDUSTRY

The use of a thermally expandable resin composition according to thepresent invention is not particularly limited. A molded product obtainedby molding said thermally expandable resin composition is excellent infire resistance and is relatively low in elastic modulus, so that theuse of refractory coating materials for pillars, beams and walls, etc.,the use of fireproof sashes, the use of fireproof compartment passagestructures and the use of fireproof doors which require high performancein fire resistance and elastic modulus are preferable. Strength of theexpansion residue after heating is high, so that the use of fireproofsashes, the use of fireproof compartment passage structures and the useof fireproof doors are more preferable.

The invention claimed is:
 1. A thermally expandable resin compositionwhich contains an epoxy resin, a thermally expandable graphite and aninorganic filler, said inorganic filler excluding graphite, saidthermally expandable resin composition being adapted for use inrefractory coating materials for pillars, beams and walls, and fireproofsashes, and fireproof compartment passage structures and in fireproofdoors, and said epoxy resin containing an epoxy compound containing abrominated epoxy compound represented by

and a bisphenol-type epoxy compound represented by Formula (1), or analiphatic epoxy compound selected from the group consisting of Formula(2), Formula (3-1), and combinations thereof:

wherein R₁ and R₂ are each independently a hydrogen atom or a methylgroup, R₃-R₆ are each independently any one of a hydrogen atom or amethyl group, Z is a repeating unit ranging from 1 to 100;

wherein R is an alkylene group having 1 to 500 carbon atoms, and cancontain an oxygen atom, n is a repeating unit ranging from 2 to 4, m isa repeating unit ranging from 0 to 1 and n+m is the range of 2-4, and

wherein R_(b) is an alkylene group having 2 to 4 carbon atoms, r is arepeating unit ranging from 1 to 500, and the ratio of a brominatedepoxy compound to at least one of a bisphenol-type epoxy compound and analiphatic epoxy compound ranges from 99:1 to 1:99 in weight.
 2. Thethermally expandable resin composition as claimed in claim 1, in whichsaid aliphatic epoxy compound is a bifunctional aliphatic epoxy compoundrepresented by

wherein R_(a) is a radical having 1 to 500 carbon atoms, and can containan oxygen atom.
 3. The thermally expandable resin composition as claimedin claim 2, in which said aliphatic epoxy compound is represented byFormula (3-2):

wherein R_(c) is an alkylene group having 2 to 10 carbon atoms.
 4. Thethermally expandable resin composition as claimed in claim 1, in whichsaid aliphatic epoxy compound is at least one selected from the groupconsisting of the Formula (4)-Formula (9)

wherein R₇ is any one of an alkylene group having 1 to 20 carbon atoms,alkenylene group having 1 to 20 carbon atoms or arylene group having 1to 20 carbon atoms;

wherein s is a repeating unit ranging from 1 to 500;

wherein t is a repeating unit ranging from 1 to 500;

wherein u is a repeating unit ranging from 1 to 500;


5. The thermally expandable resin composition as claimed in claim 1, inwhich said aliphatic epoxy compound contains

wherein R is an alkylene group having 1 to 500 carbon atoms, and cancontain an oxygen atom, q is a repeating unit ranging from 3 to 4, p isa repeating unit ranging from 0 to 1 and p+q is the range of 3-4.
 6. Thethermally expandable resin composition as claimed in claim 5, in whichsaid aliphatic epoxy compound is at least one selected from the groupconsisting of the Formula (10)-Formula (12)


7. The thermally expandable resin composition as claimed in claim 4, inwhich said epoxy resin contains an amino compound-containing epoxycuring agent, and said amino compound-containing epoxy curing agentcontains at least one selected from the group consisting of Formula(13)-Formula (16)R₈—O—R₉—NH₂  Formula (13) wherein R₈ is an alkylene group having 1 to 20carbon atoms, alkenyl group having 1 to 20 carbon atoms or aryl grouphaving 1 to 20 carbon atoms, may contain an oxygen atom, R₉ is analkylene group having 1 to 20 carbon atoms, alkenylene group having 1 to20 carbon atoms or arylene group having 1 to 20 carbon atoms, maycontain an oxygen atom

wherein R₁₀ and R₁₁ are each independently a hydrogen atom, an alkylgroup having 1 to 20 carbon atoms, alkenyl group having 1 to 20 carbonatoms or aryl group having 1 to 20 carbon atoms

wherein R₁₂, R₁₃ and R₁₄ are each independently a hydrogen atom, analkyl group having 1 to 20 carbon atoms, alkenyl group having 1 to 20carbon atoms or aryl group having 1 to 20 carbon atoms, may contain anoxygen atomR₁₅—NH₂  Formula (16) wherein R₁₅ is each independently an alkyl grouphaving 1 to 20 carbon atoms, alkenyl group having 1 to 20 carbon atomsor aryl group having 1 to 20 carbon atoms, may contain an oxygen atom.8. The thermally expandable resin composition as claimed in claim 6, inwhich said epoxy resin contains an amino compound-containing epoxycuring agent, and said amino compound-containing epoxy curing agentcontains at least one selected from the group consisting of Formula(13)-Formula (16)R₈—O—R₉—NH₂  Formula (13) wherein R₈ is an alkylene group having 1 to 20carbon atoms, alkenyl group having 1 to 20 carbon atoms or aryl grouphaving 1 to 20 carbon atoms, may contain an oxygen atom, R₉ is analkylene group having 1 to 20 carbon atoms, alkenylene group having 1 to20 carbon atoms or arylene group having 1 to 20 carbon atoms, maycontain an oxygen atom

wherein R₁₀ and R₁₁ are each independently a hydrogen atom, an alkylgroup having 1 to 20 carbon atoms, alkenyl group having 1 to 20 carbonatoms or aryl group having 1 to 20 carbon atoms

wherein R₁₂, R₁₃ and R₁₄ are each independently a hydrogen atom, analkyl group having 1 to 20 carbon atoms, alkenyl group having 1 to 20carbon atoms or aryl group having 1 to 20 carbon atoms, may contain anoxygen atomR₁₅—NH₂  Formula (16) wherein R₁₅ is each independently an alkyl grouphaving 1 to 20 carbon atoms, alkenyl group having 1 to 20 carbon atomsor aryl group having 1 to 20 carbon atoms, may contain an oxygen atom.9. The thermally expandable resin composition as claimed in claim 7, inwhich said inorganic filler is ammonium polyphosphate and calciumcarbonate.
 10. The thermally expandable resin composition as claimed inclaim 8, in which said inorganic filler is ammonium polyphosphate andcalcium carbonate.